Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

10" Dobsonians that don't need a Paracorr

  • Please log in to reply
102 replies to this topic

#101 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 103,629
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted Yesterday, 05:26 AM

Making a scope faster so you can sit while you observe is a compromise. Using a coma corrector is a compromise. Dealing with a large secondary mirror is also a compromise. A long, slow reflector that performs like an APO refractor is a no compromise scope.

 

The slow reflector compromises big time. It compromises aperture, far more important than focal ratio in resolving planetary detail.

 

I'll take my 16 inch F/4.4 as a planetary/double star scope over an 8 inch F/8.8.. 

 

Once you step away from comparing scopes of equal apertures, it's a new Paradigm. 

 

Jon



#102 CHASLX200

CHASLX200

    ISS

  • *****
  • Posts: 28,620
  • Joined: 29 Sep 2007
  • Loc: Tampa area Florida

Posted Yesterday, 06:46 AM

Looks like a sister to my 1968 built 10” f8 from one of Dobson’s early classes in San Francisco. That’s me around 1969 with my first refractor bought a few years prior.

Never knew there was a Dob in 1969.


  • MeridianStarGazer and therealdmt like this

#103 25585

25585

    James Webb Space Telescope

  • *****
  • Posts: 17,991
  • Joined: 29 Aug 2017
  • Loc: In a valley, in the SW UK. 51°N

Posted Today, 08:50 AM

I’m all for them. Unfortunately, no one makes them, as far as I know. They’re more portable, and simply rolling up the shroud, or leaving it off altogether, is an easy way to deal with tube currents.

You can get 8" SW Collapsible Dobs, nearest commercial I expect. They must be quite compact when collapsed, and being F6 collimation will be less critical.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics